The Type IX U-boat was a development of the Type VII U-boat. It was an excellent ocean-going submarine, capable of operating in great distant waters and far more spacious and comfortable than the Type VII. Its bigger size, however, meant that its diving speed was rather slower than the Type VII. Without the external saddle tanks of the Type VII, the Type IX was a much sleeker looking boat and had greater fore and aft deck space. She had six torpedo tubes, four in the bow and two astern. Up to 23 torpedoes were stored. Secondary armament was provided by one 105 mm deck gun with about 110 rounds. AA armament differed throughout the war.